One practice of fabricating a window sash having an insulating viewing or vision area includes fabricating an insulating glazing unit and mounting the glazing unit in an open area defined by a sash frame. As used throughout this document, the term “sash frame” means a framework made up of one or more straight and/or bent elongated sash members or lineals defining an enclosed open area, and the terms “sash” or “window sash” mean a sash frame having one or more sheets, e.g. but not limited to one or more glass sheets in the enclosed open area bound by the sash frame which area, when having one or more transparent sheets therein, provides a viewing area. The insulating unit can be made in any manner, for example, but not limited to the techniques disclosed in U.S. Pat. Nos. 5,177,916; 5,531,047; 5,553,440; 5,564,631; 5,617,699; 5,644,894; 5,655,282; 5,720,836; 6,115,989; 6,250,026, and 6,289,641. The adjacent sheets of the insulating units are maintained in a spaced relationship to one another by a spacer frame, and the inner marginal edges of the sheets are secured to the spacer frame by a gas and vapor resistant adhesive to provide a sealed gas space or compartment between the adjacent sheets.
In another practice, a glass sheet is secured to each of the ledges of two or more sheet supporting ledges of a sash frame to space the sheets from one another to provide an insulating vision area, for example, as disclosed in U.S. Pat. Nos. 5,653,073 and 6,055,783.
As can be appreciated by those skilled in the art of fabricating window sashes having insulating vision areas, eliminating the manufacturing steps to make an insulating unit significantly reduces the cost of manufacturing a window sash having an insulating viewing area. Although the presently available practices of fabricating window sashes having insulating viewing areas without prefabricated insulating glazing units are acceptable, it can be appreciated by those skilled in the art that it is advantageous to have additional techniques to fabricate such window sashes.